1. Field of the Invention
The present invention relates to a waterproof camera of a daily-use water resistant type which incorporates a lens tube advancing and retracting apparatus in the direction of an optical-axis.
2. Related Background Art
In the daily-use water resistant type of conventional camera having a photographing lens tube which advances and retracts, the camera is kept in a watertight state. Hence, an internal volume of the watertight camera changes with the advancing and retracting movements based on a zooming drive of the photographing lens tube and a collapsible driving action thereof, and an internal pressure is thereby varied. A resistance force during the drive of the lens tube largely changes due to the variation in the internal pressure thereof. Besides, there exists a possibility in which the internal pressure becomes negative with respect to the outside air, and the watertightness can not be kept. To cope with this, according to a drip-proof camera disclosed in Japanese Utility Model Laid-Open Publication No. 113137/1988, a breeze hole is formed in a main frame of the camera having the advanceable/retractable photographing lens tube, and a filter composed of a non-water-permeable but air-permeable material (e.g., GORE TEX (brand name) made by JAPAN CORE TEX Corp.) is disposed therein. The above-mentioned inconvenience is thus eliminated.
However, the above-stated drip-proof camera disclosed in Japanese Utility Model Laid-Open Publication No. 113137/1988 involves the use of the filter of the expensive material exhibiting both the non-water-permeability and air-permeability. This is disadvantageous in terms of cost. An additional inconvenience is such that because of using the above-mentioned filter, the water droplets which have mistakenly entered the camera during an exchange of the film can not be discharged from the camera and therefore remain inside.